Solve for $x$ and $y$ using substitution. ${-2x+4y = 2}$ ${x = -4y-7}$
Answer: Since $x$ has already been solved for, substitute $-4y-7$ for $x$ in the first equation. ${-2}{(-4y-7)}{+ 4y = 2}$ Simplify and solve for $y$ $8y+14 + 4y = 2$ $12y+14 = 2$ $12y+14{-14} = 2{-14}$ $12y = -12$ $\dfrac{12y}{{12}} = \dfrac{-12}{{12}}$ ${y = -1}$ Now that you know ${y = -1}$ , plug it back into $\thinspace {x = -4y-7}\thinspace$ to find $x$ ${x = -4}{(-1)}{ - 7}$ $x = 4 - 7$ ${x = -3}$ You can also plug ${y = -1}$ into $\thinspace {-2x+4y = 2}\thinspace$ and get the same answer for $x$ : ${-2x + 4}{(-1)}{= 2}$ ${x = -3}$